Submitted to: Annual Southern Conservation Tillage Conference for Sustainable Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: 5/15/2006
Publication Date: 6/15/2006
Citation: Chebrolu, K.K., Robinson, C.A., Gowda, P., Stewart, B.A. 2006. Characterization of precipitation trends in the Ogallala Aquifer region. In: Proceedings of the 28th Annual Southern Conservation Tillage Conference, June 26-28, 2006, Amarillo, Texas. p. 278.
Technical Abstract: Ideally, researchers and practitioners would like to be able to forecast precipitation pattern so that strategies can be developed to manage limited water resources. This is particularly important for regions where depleting ground water is the main source of water supply for agricultural purposes. Also, changes in precipitation trends affect the crop growth and management practices. However, current precipitation forecasting capability is limited. Given the demand for such information, it seems timely that the basic statistics of precipitation variability and its relationship with variability at a regional scale should be thoroughly examined. A long-term data set of daily precipitation at 22 stations located between -104 degrees to -100 degrees W longitude and 33 degrees to 42 degrees N latitude was used to characterize the precipitation trends within the Ogallala Aquifer Region from Nebraska to Texas panhandle. A detailed analysis identified precipitation trends, number of events and amounts and events by class across the Ogallala Aquifer Region. More than 50 percent of the annual precipitation occurs during the cropping season (May-September). Spatial analysis indicated annual precipitation increases with decrease in longitude (west to east). The smaller precipitation events (0.25-5 mm) account for more than 50 percent of the events per year, but produce only 13.7 percent of the annual average precipitation. Events with 5 to 50 mm account for 41 percent of the total events per year, but produce about 77 percent of the total annual precipitation. Results also indicate that there has been an increase in the number of precipitation events mainly due to increase in the number of low to moderate intensity events. This trend is consistent irrespective of rain-gauge location. Also, it was observed that annual average precipitation has been increased but was not statistically significant.